Conventionally, automotive vehicle sunroofs consist of glass or a synthetic resin and include a strip which is fitted on its four sides at its edges. The strip is provided with a seal so that when closing the window opening formed in the roof of the vehicle the sunroof forms a hermetic seal between the sunroof and the window opening. Drive means is employed to raise and lower the sunroof to open and close the window opening. To close the window opening, first the forward part of the sunroof is raised to a predetermined position, then the rearward part of the sunroof is raised so that the seal on the rearward edge of the sunroof is urged strongly against the corresponding rearward edge of the window opening. Although the strong urging pressure is desirable for hermetically sealing the joint between the sunroof and window opening, deformation of the sunroof results because the rearward side of the sunroof is caused to bend or flex. As a result the quality of the hermetic seal between the sunroof and window opening, especially on the rearward side of the sunroof is eventually diminished.